1. Field of the Invention
The present invention relates to a lens barrel and a lens unit.
2. Description of the Related Art
A conventionally known lens barrel includes: a rotatable lens drive cylinder that moves and operates a lens in the optical axis direction; a rotatable input transmission ring that is connected to the lens drive cylinder in such a manner that rotating force can be transmitted; and a motor that rotationally drives the input transmission ring. For example, JP 2012-27060 A discloses such a lens barrel.
In the lens barrel disclosed in JP 2012-27060 A, the lens drive cylinder is placed on one side of the motor in the optical axis direction, and the input transmission ring is placed on the other side of the motor in the optical axis direction. The lens drive cylinder and the input transmission ring are connected by two connecting levers in such a manner that rotating force can be transmitted.
In JP 2012-27060 A, however, the lens drive cylinder and the input transmission ring that are placed on both sides of the motor in the optical axis direction are connected by two connecting levers. Therefore, the connecting levers should be placed on the outer side of the motor in the radial direction, for example, so that the two connecting levers will not be brought into contact with the motor. Where the connecting levers are placed on the outer side of the motor in the radial direction, the entire lens barrel is large in radius. The connecting levers can be placed on the circumferential-direction side of the motor so that the two connecting levers will not be brought into contact with the motor. However, where the connecting levers are placed on the circumferential side of the motor, the rotation ranges of the connecting levers in the circumferential direction are limited, resulting in a smaller number of rotations of the lens drive cylinder.
In addition, since the lens drive cylinder and the input transmission ring are connected by two connecting levers, the two connecting levers need to simultaneously transmit the rotating force of the rotating input transmission ring to the lens drive cylinder. Therefore, the two connecting levers should be attached to the lens drive cylinder and the input transmission ring with high precision.